From d847f80334498bde6993b8f3a38c7df05d83b47b Mon Sep 17 00:00:00 2001
From: Anton Tananaev <anton.tananaev@gmail.com>
Date: Mon, 26 Mar 2018 06:45:10 +1300
Subject: Implement EGTS responses

---
 src/org/traccar/helper/Checksum.java | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

(limited to 'src/org/traccar/helper')

diff --git a/src/org/traccar/helper/Checksum.java b/src/org/traccar/helper/Checksum.java
index 43ba6a689..c4141e7d2 100644
--- a/src/org/traccar/helper/Checksum.java
+++ b/src/org/traccar/helper/Checksum.java
@@ -129,6 +129,33 @@ public final class Checksum {
         0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040,
     };
 
+    private static final int[] CRC8_TABLE = {
+            0x00, 0x31, 0x62, 0x53, 0xC4, 0xF5, 0xA6, 0x97,
+            0xB9, 0x88, 0xDB, 0xEA, 0x7D, 0x4C, 0x1F, 0x2E,
+            0x43, 0x72, 0x21, 0x10, 0x87, 0xB6, 0xE5, 0xD4,
+            0xFA, 0xCB, 0x98, 0xA9, 0x3E, 0x0F, 0x5C, 0x6D,
+            0x86, 0xB7, 0xE4, 0xD5, 0x42, 0x73, 0x20, 0x11, 0x3F,
+            0x0E, 0x5D, 0x6C, 0xFB, 0xCA, 0x99, 0xA8, 0xC5, 0xF4, 0xA7, 0x96,
+            0x01, 0x30, 0x63, 0x52, 0x7C, 0x4D, 0x1E, 0x2F, 0xB8, 0x89, 0xDA,
+            0xEB, 0x3D, 0x0C, 0x5F, 0x6E, 0xF9, 0xC8, 0x9B, 0xAA, 0x84, 0xB5,
+            0xE6, 0xD7, 0x40, 0x71, 0x22, 0x13, 0x7E, 0x4F, 0x1C, 0x2D, 0xBA,
+            0x8B, 0xD8, 0xE9, 0xC7, 0xF6, 0xA5, 0x94, 0x03, 0x32, 0x61, 0x50,
+            0xBB, 0x8A, 0xD9, 0xE8, 0x7F, 0x4E, 0x1D, 0x2C, 0x02, 0x33, 0x60,
+            0x51, 0xC6, 0xF7, 0xA4, 0x95, 0xF8, 0xC9, 0x9A, 0xAB, 0x3C, 0x0D,
+            0x5E, 0x6F, 0x41, 0x70, 0x23, 0x12, 0x85, 0xB4, 0xE7, 0xD6, 0x7A,
+            0x4B, 0x18, 0x29, 0xBE, 0x8F, 0xDC, 0xED, 0xC3, 0xF2, 0xA1, 0x90,
+            0x07, 0x36, 0x65, 0x54, 0x39, 0x08, 0x5B, 0x6A, 0xFD, 0xCC, 0x9F,
+            0xAE, 0x80, 0xB1, 0xE2, 0xD3, 0x44, 0x75, 0x26, 0x17, 0xFC, 0xCD,
+            0x9E, 0xAF, 0x38, 0x09, 0x5A, 0x6B, 0x45, 0x74, 0x27, 0x16, 0x81,
+            0xB0, 0xE3, 0xD2, 0xBF, 0x8E, 0xDD, 0xEC, 0x7B, 0x4A, 0x19, 0x28,
+            0x06, 0x37, 0x64, 0x55, 0xC2, 0xF3, 0xA0, 0x91, 0x47, 0x76, 0x25,
+            0x14, 0x83, 0xB2, 0xE1, 0xD0, 0xFE, 0xCF, 0x9C, 0xAD, 0x3A, 0x0B,
+            0x58, 0x69, 0x04, 0x35, 0x66, 0x57, 0xC0, 0xF1, 0xA2, 0x93, 0xBD,
+            0x8C, 0xDF, 0xEE, 0x79, 0x48, 0x1B, 0x2A, 0xC1, 0xF0, 0xA3, 0x92,
+            0x05, 0x34, 0x67, 0x56, 0x78, 0x49, 0x1A, 0x2B, 0xBC, 0x8D, 0xDE,
+            0xEF, 0x82, 0xB3, 0xE0, 0xD1, 0x46, 0x77, 0x24, 0x15, 0x3B, 0x0A,
+            0x59, 0x68, 0xFF, 0xCE, 0x9D, 0xAC };
+
     // More info: http://reveng.sourceforge.net/crc-catalogue/16.htm
     public static final String CRC16_IBM = "IBM";
     public static final String CRC16_MODBUS = "MODBUS";
@@ -181,6 +208,14 @@ public final class Checksum {
         }
     }
 
+    public static int crc8(ByteBuffer buf) {
+        int crc = 0xFF;
+        while (buf.hasRemaining()) {
+            crc = CRC8_TABLE[(crc ^ buf.get()) & 0xFF];
+        }
+        return crc & 0xFF;
+    }
+
     public static int crc32(ByteBuffer buf) {
         CRC32 checksum = new CRC32();
         while (buf.hasRemaining()) {
-- 
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